The invention relates to apparatus and a method of changing the cross-sectional format of a strand when continuously casting strands with a mould, at least one side wall of the mould being adjusted relative to an opposite mould side wall, and its inclination being changed.
For changing the cross-sectional format of a strand, such as e.g. for changing the strand width of a slab, the continuous casting process hitherto has had to be interrupted. It was only after displacing the mould narrow sides to the new cross-sectional format of the strand, that the casting process could be started anew by using a starter bar, and this only after having carried out the necessary set-up. This resulted first in a loss of production due to the time expenditure necessary for setting up the plant, and secondly in a deterioration of the yield due to the resulting end and starting scrap, and due to the resulting residual steel in the distributor vessel.
From German Offenlegungsschrift No. 2,018,962, a specially designed mould is known with which the changing of the format of a strand is feasible without using a starter bar. For this purpose, the mould comprises mould side walls that are subdivided at half-height. For changing the format, at first the bath level in the mould is lowered to below the divisional plane of the mould side walls. Then the upper wall parts of the divided side walls are each laterally displaced in accordance with the new cross-sectional format of the strand, whereupon a specially manufactured cooling scrap container containing cooling scrap is inserted. The bath level is next raised, and finally the lower wall part of the divided mould narrow side wall is laterally displaced in accordance with the upper wall part. Changing of the format according to German Offenlegungsschrift No. 2,018,962 is cumbersome to carry out, requires an interruption of the casting process and a complex design of the mould. Furthermore, the production of cooling scrap containers is necessary, which--as regards their dimensions--have to precisely correspond to the new and to the old cross-sectional formats of the strand. Insertion of the cooling scrap containers requires additional manipulations.